OpenDKIM and MailScanner

Ken Smith kens at
Tue Apr 24 22:02:01 UTC 2018

*From:* MailScanner 
< at> on behalf of 
Ken Smith <kens at>
*Sent:* Thursday, April 12, 2018 4:23 AM
*To:* MailScanner Discussion
*Subject:* OpenDKIM and MailScanner

Hullo - I'm new to this list but been a MailScanner user for 10+ years.

I have an installation of M'Scanner 5.0.7 on Centos 6 with Sendmail. I'd
like to have all e-mail go out with an appended footer that has company
standard signature / disclaimers etc etc. I'm also using DKIM.


The catch appears to be that the message body has been modified, footer
added etc,  after the DKIM signature has been calculated and thus the
DKIM checks fail on delivery. :-(

Would it be possible to arrange for the DKIM signature to be calculated
by the outgoing sendmail on the completed message? This might involve
two different .cf files. One without the DKIM milter for the incoming
Sendmail and one with DKIM settings for the outgoing.


Many thanks


David Jones via MailScanner wrote:
> Setup 2 different OpenDKIM instances and run the checking/header 
> adding one on smtpd_milters and the other signing one on 
> non_smtpd_milters.
> Dave

Hi list and Dave,

I'd like to try a variation on this idea

Its not clear to me whether the example in that web site implies that 
the machine is configured with two IP's or whether there are two 
machines, as I have also seen described elsewhere. I'd prefer to run an 
extra instance of sendmail with outgoing DKIM, rather than a second 
server.  In this case I don't require incoming DKIM, although that would 
be a bonus. I've experimented with an extra sendmail instance listening 
on port 26 based on the existing sendmail daemon configuration with its 
own .cf file. With the ms-sendmail instances + MailScanner sending out 
via a smart host on localhost:26.

But I think I'm not properly understanding the roles of the 3 sendmail 
instances that are started by the ms-sendmail init script.  I appreciate 
that I need to have separate queue's and pid etc. In my test setup it 
appears that the ms-sendmail instance is ignoring my smarthost settings 
and just sending out based on mx. I have missed some subtle detail 

Could someone kindly explain three instances or point me to a clear 
explanation of what the three instances of sendmail are doing. In 
particular the two that appear to be started by the incoming part of the 

Much appreciated


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